The interoperable master format: A gateway to component-based workflows

Professional media continues its inexorable march towards component-based workflows, where the elements of a presentation - audio, video, timed text - are stored and processed individually, to be assembled just in time to meet the specific needs of each distribution channel, writes IMF User Group chair and partner at Sandflow Consulting Pierre-Anthony Lemieux.

Component-based workflows are designed to tackle the explosion in the number of content versions resulting from proliferation of localised versions due to worldwide distribution and acquisition, multiplication of viewing experiences as well as the expanding repertoire of audio-visual essence, such as access services, immersive sound, HDR, 4K.

Pierre-Anthony Lemieux

The Interoperable Master Format (IMF) family of standards, managed by SMPTE and in active use, is designed for the interchange of component-based audio-visual masters – from movies to adverts.

At the heart of IMF is the Composition Playlist (CPL), which is an XML document that defines the timeline for one version of the master. The essence and metadata associated with the timeline are usually stored in separate MXF files called Track Files.

An IMF Composition is the combination of a Composition Playlist and all the Track Files it references. The same portion of a Track File can be referenced by any number of Composition Playlists, allowing multiple content versions to reuse the same essence. This approach dramatically:

• Accessibility: Accessible on any connected device, even mobile phones, and anywhere in the world.

• Security: Decreases the attack surface by reducing the number of entities handling cloud content – in contrast to manually moving files from workstation to workstation, over networks or hard drives or tape, – and also benefits from the specialised security expertise of cloud platform providers.

Unique challenges While adopting new technologies always requires time and education, cloud-based solutions face a number of unique challenges. One of these is interactivity; due to network latency and web-platform limitations, some specialised tools, for example colour grading, remain off-limits for now.

There are also technical bottlenecks, and standards need to be revised to make optimal use of cloud parallel processing, for example, hashing of Track Files.

There are also challenges to business models. Subscription or compute cycles pricing models are a stark departure from traditional costs measured in workstation or jobs.

The IMF User Group (IMF UG) was formed to be an open forum for the community of IMF users and implementers. It is organised under the Hollywood Professional Association (HPA) umbrella and currently has 87 members, from large multinationals to individuals.

The IMF UG offers a unique opportunity for IMF users and implementers to communicate directly with each other, and to co-ordinate best practices based on operational experience. Recent examples include best practices for the use of EIDR and ISAN identifiers to enable workflow automation.

As more of professional media moves beyond traditional HD workflows, the demand for component-based and cloud-based workflows, enabled by technologies such as IMF, will grow. Join us in the IMF UG to be at the forefront of these developments.

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